Wrist and forearm exercising devices have previously been disclosed in the art, certain of said devices having hand grips which are twisted in relation to each other about a longitudinal axis. In such devices, resistance to torsional forces imparted to the devices by a user is typically accomplished by friction brake members, cam devices, and springs. Devices utilizing a flat spring member as the resistive portion and which are further capable of varying torsional resistance have also been available according to the teachings of the prior art, torsion being varied in such devices by the replacement of one flat steel spring member with a second spring member having a different elasticity. U.S. patents which disclose such spring devices include:
U.s. pat. No. 2,668,055--Feb. 2, 1954 PA1 U.s. pat. No. 2,818,253--Dec. 31, 1957 PA1 U.s. pat. No. 3,084,547--Apr. 9, 1963 PA1 U.s. pat. No. 3,211,453--Oct. 12, 1965 PA1 U.s. pat. No. 3,330,558--July 11, 1967 PA1 U.s. pat. No. 3,708,164--Jan. 2, 1973.
These prior devices do not disclose an exerciser unit wherein the torsional resistance of said unit can be varied by longitudinally adjusting the point of connection between at least one of the hand grip members comprising the device and a flat spring utilized within the device to resist axial displacement of portions of the device relative to each other.
The present invention provides an exerciser device for strengthening the wrist, forearm and elbow, the present device including an adjustment mechanism which is useful in other exercising devices wherein the torsional resistance of the device is intended to be adjustable. In particular, the present invention provides means for adjusting the torsional resistance of two axially movable portions of an exercising device, the adjustment means particularly comprising mechanisms for varying the effective length, and thus the tension, of one or more spring members effectively joined to the axially movable portions of said device. Major portions of the present adjustment mechanisms are disposed interiorly of the device itself, at least one of the axially movable portions being preferably formed of a clear material in order that the adjustment of the spring tension can be visually observed. In a preferred embodiment of the invention, a pair of tubular members aligned along the longitudinal axis thereof and movable axially relative to each other form a housing enclosing a rod threaded along at least a portion thereof, the threaded portion of the rod being attached to a knob disk member disposed at one end of the device, the rod being mounted for rotation within the housing formed by the tubular members. A pair of flat spring members stationarily mounted at the end of the device opposite the knob member extends longitudinally along the rod in spaced relation thereto and preferably on opposite sides thereof. The flat spring members are each received within slot-like apertures formed in an adjustment disk, the adjustment disk having a central aperture formed therein for receiving the threaded portion of the rod therethrough, the adjustment disk being movable longitudinally of the rod on rotation of said rod by means of axial displacement of the knob member by a user of the device. Since the flat spring members are stationarily attached at one end of the device and effectively attached at the other end of the device at a variable location thereof by the adjustment disk, the torsional resistance evidenced by the exerciser device is thus varied according to the needs of a user.
Accordingly, it is an object of the present invention to provide an exerciser device for strengthening of the wrist, forearm and elbow which is capable of varying resistance to attempts by a user to operate said device, variance of the resistance of the device being effected by a simple external adjustment not requiring replacement of any portion of the device.
It is a further object of the invention to provide an adjustment mechanism for an exerciser device for varying the torsional resistance of the device without the necessity for access into the internal portions of said device.
These together with other objects and advantages which will become subsequently apparent reside in the details of construction and operation as more fully hereinafter described and claimed, reference being had to the accompanying drawings forming a part hereof, wherein like numerals refer to like parts throughout.